Highly soluble modified epoxy resin composition

ABSTRACT

An epoxy resin composition in a liquid or solid state having excellent solubility and having high preservation stability. A modified epoxy resin composition including: Compound A containing tris-(2,3-epoxypropyl)-isocyanurate having 1 to 3 glycidyl group(s) in a molecule substituted with a functional group(s) of Formula (1): 
                         
in which R 1  and R 2  are each independently an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an aralkyl group, a heterocyclic group; or a halogenated derivative, an aminated derivative, or a nitrated derivative of these groups; and Compound B containing tris-(2,3-epoxypropyl)-isocyanurate, wherein tris-(2,3-epoxypropyl)-isocyanurate of Compound A before the substitution and tris-(2,3-epoxypropyl)-isocyanurate of Compound B comprise 2% by mass to 15% by mass of β-type tris-(2,3-epoxypropyl)-isocyanurate and a remaining percentage of α-type tris-(2,3-epoxypropyl)-isocyanurate based on a total mass of Compound A before the substitution and Compound B.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a Continuation of application Ser. No. 15/105,935 filed Jun. 17,2016, which in turn is a national stage entry of PCT/JP2014/082695 filedDec. 10, 2014, which claims priority to JP 2013-259971 filed Dec. 17,2013. The disclosure of the prior applications is hereby incorporated byreference herein in its entirety.

TECHNICAL FIELD

The present invention relates to a liquid modified epoxy resin that ismodified without largely impairing inherent curing characteristics ofpolyfunctional epoxy resins in order to improve solubility to solventsand curing agents and preservation stability, so that an applicationrange becomes broader.

BACKGROUND ART

Crystalline epoxy resins are used in fields that require reliable heatresistance, such as an electric/electronic field, because they commonlyhave rigid main chain backbones and are polyfunctional, and thus theyare highly heat resistant.

However, only liquid compositions can work for certain uses such as castmolding, and thus crystalline epoxy resins are predominantly used foruses of solid materials, such as a transfer molding.

Also, epoxy resins used for liquid molding, such as cast molding, areliquid epoxy resins, which do not satisfy strict demands forimprovements of curing characteristics, such as heat resistance, inrecent fields of adhesion, cast molding, sealing, molding, lamination,and the like. Therefore, a demand for liquefaction of crystallinepolyfunctional epoxy resins that give curing characteristics having highheat resistance has been raised. Meanwhile, a demand for stability ofcured products in short wavelength regions, corresponding to white LEDsand blue LEDs, has also been raised.

Patent Document 1 describes a modified liquid epoxy resin obtained byreacting a crystalline epoxy resin with a compound that has two or morephenolic hydroxy groups and/or carboxy groups in a molecule and acompound that has one phenolic hydroxy group and/or one carboxy group ina molecule.

Patent Document 2 describes a method for manufacturing a liquid epoxyresin composition that is flowable in a room temperature, in which amixture containing a crystalline epoxy resin and a liquid acid anhydridecuring agent is melted and mixed for 10 minutes or longer at atemperature equal to or higher than the melting point of the epoxy resinto react the mixture to obtain a non-crystalline epoxy resin.

Patent Document 3 describes a tris-(2,3-epoxypropyl)-isocyanuratecomposition that is liquid at a room temperature, composed of: 100 partsby weight of the low melting point-type stereoisomer oftris-(2,3-epoxypropyl)-isocyanurate having a melting point of 98° C. to107° C. and an epoxy value of 9.9 or more; and certain parts by weightof a curing agent, in which a ratio of a carboxylic anhydride to oneepoxy group in a total epoxy resin is 0.5 to 1.5.

Patent Document 4 describes a method for preventing crystallization,which is for preventing solidification by recrystallization of a liquidcomposition containing a trivalent epoxy compound having a triazinenucleus as its backbone and an acid anhydride curing agent,characterized in that a moisture percentage in the composition is keptat 0.5% by weight or less.

Patent Document 5 describes a liquid epoxy resin composition in which αcrystalline tris-(2,3-epoxypropyl)-isocyanurate having high solubilityis reacted with an acid anhydride such as acetic anhydride. However, amanufacturing method of the tris-(2,3-epoxypropyl)-isocyanuratecontaining only α crystals, and not containing β crystals having lowsolubility is not described at all. In addition, in order to manufacturethe tris-(2,3-epoxypropyl)-isocyanurate containing only α crystals, andnot containing β crystals, recrystallization needs to be repeated toremove β crystals, which results in low recovery, and thus this is notpreferable as an industrial manufacturing method.

PRIOR ART DOCUMENTS Patent Documents

Patent Document 1: Japanese Patent Application Publication No. H7-62060(JP 07-62060 A)

Patent Document 2: Japanese Examined Patent Application Publication No.H6-68014 (JP 06-68014 B)

Patent Document 3: Japanese Patent Application Publication No. H4-264123(JP 04-264123 A)

Patent Document 4: Japanese Patent Application Publication No. H4-81420(JP 04-81420 A)

Patent Document 5: International Publication WO 2006/035641 Pamphlet

SUMMARY OF THE INVENTION Problem to be Solved by the Invention

Recently, especially in an electric/electronic field, extremely superiorcharacteristics are required for epoxy resin cured products used,because of highly integrated circuits, uses of lead-free solder, and thelike. Accordingly, the characteristics described above (heat resistance,water absorption inhibitory activity, and mechanical properties) aredifficult to be satisfied with conventional modified epoxy resins.

Meanwhile, liquid epoxy resins have been conventionally used forpotting, coating, casting, and the like, because of theircharacteristics, such as easy handling and reduced occurrence oftroubles in manufacturing such as elevation of viscosity bycrystallization.

Therefore, in order to obtain superior characteristics of liquid epoxyresins, a demand for liquefaction of crystalline epoxy resins, such aspolyfunctional epoxy resins, which give cured products having superiorphysical properties, such as high heat resistance, has been raised toexpand the range of uses.

Also, a demand for epoxy resins that retain heat resistance and the likeas advantages of polyfunctional epoxy resin cured products, improvesolubility to solvents and curing agents, and has higher preservationstability has been raised.

In order to satisfy the demanded characteristics described above, thepresent invention provides a liquid or solid epoxy resin compositionhaving high solubility to solvents and curing agents and having higherpreservation stability, by modifying crystallinetris-(2,3-epoxypropyl)-isocyanurate, in which the content of low-solubleβ crystals is low, with an acid anhydride.

Means for Solving the Problem

The present invention is: as a first aspect, a modified epoxy resincomposition characterized by comprising Compound A containingtris-(2,3-epoxypropyl)-isocyanurate having 1 to 3 glycidyl group(s) in amolecule substituted with a functional group(s) of Formula (1):

(wherein, R¹ and R² are each independently an alkyl group, an alkenylgroup, an alkynyl group, an aryl group, an aralkyl group, a heterocyclicgroup; or a halogenated derivative, an aminated derivative, or anitrated derivative of these groups) and Compound B containingtris-(2,3-epoxypropyl)-isocyanurate, in whichtris-(2,3-epoxypropyl)-isocyanurate of Compound A before thesubstitution and tris-(2,3-epoxypropyl)-isocyanurate of Compound Bcomprise 2% by mass to 15% by mass of β-typetris-(2,3-epoxypropyl)-isocyanurate and a remaining percentage of α-typetris-(2,3-epoxypropyl)-isocyanurate based on a total mass oftris-(2,3-epoxypropyl)-isocyanurate of Compound A before thesubstitution and tris-(2,3-epoxypropyl)-isocyanurate of Compound B;

as a second aspect, the modified epoxy resin composition according tothe first aspect, in which a molar ratio of Compound A:Compound B is90:10 to 30:70;

as a third aspect, the modified epoxy resin composition according to thefirst aspect or the second aspect, in whichtris-(2,3-epoxypropyl)-isocyanurate of Compound A before thesubstitution and tris-(2,3-epoxypropyl)-isocyanurate of Compound Bcomprise 2% by mass to 10% by mass of β-typetris-(2,3-epoxypropyl)-isocyanurate and a remaining percentage of α-typetris-(2,3-epoxypropyl)-isocyanurate based on a total mass oftris-(2,3-epoxypropyl)-isocyanurate of Compound A before thesubstitution and tris-(2,3-epoxypropyl)-isocyanurate of Compound B;

as a fourth aspect, a method for manufacturing the modified epoxy resincomposition described in any one of the first to the third aspects,comprising: separating β-type tris-(2,3-epoxypropyl)-isocyanuratecontained in a tris-(2,3-epoxypropyl)-isocyanurate solution from thesolution as a solid, and obtaining a crystalline body having anincreased content ratio of α-type tris-(2,3-epoxypropyl)-isocyanuratefrom the solution, as Step (i); obtaining atris-(2,3-epoxypropyl)-isocyanurate crystalline body having a furtherincreased content ratio of α-type tris-(2,3-epoxypropyl)-isocyanuratefrom the crystalline body obtained in Step (i) by extracting β-typetris-(2,3-epoxypropyl)-isocyanurate with a solvent, as Step (ii); andreacting the tris-(2,3-epoxypropyl)-isocyanurate crystalline bodyobtained in Step (ii) with an acid anhydride, provided that a molarratio of (glycidyl groups):(acid anhydrides) is 1:0.05 to 0.5, as Step(iii);

as a fifth aspect, the method for manufacturing the modified epoxy resincomposition described in the fourth aspect, in which the extraction inStep (ii) is performed with a heated solvent;

as a sixth aspect, the method for manufacturing the modified epoxy resincomposition described in the fourth or fifth aspect, in which thesolvent in the tris-(2,3-epoxypropyl)-isocyanurate solution in Step (i)is methyl ethyl ketone, acetone, acetonitrile, ethyl acetate, orepichlorohydrin;

as a seventh aspect, the method for manufacturing the modified epoxyresin composition described in any one of the fourth to sixth aspects,in which the solvent used for extracting β-typetris-(2,3-epoxypropyl)-isocyanurate in Step (ii) is methyl ethyl ketone,acetone, methanol, ethanol, or isopropanol (2-propanol);

as an eighth aspect, the method for manufacturing the modified epoxyresin composition described in any one of the first to third aspects,comprising Steps (A), (B), (i′), and (iii) below:

Step (A): producing an epichlorohydrin adduct of cyanuric acid byreacting 1 mol of cyanuric acid with 5 mol to 180 mol ofepichlorohydrin, and obtaining a solution containingtris-(2,3-epoxypropyl)-isocyanurate by dehydrochlorinating the adduct;

Step (B): adjusting a solid content concentration of the solutioncontaining tris-(2,3-epoxypropyl)-isocyanurate obtained in Step (A) to10% by mass to 50% by mass;

Step (i′): separating β-type tris-(2,3-epoxypropyl)-isocyanuratecontained in the tris-(2,3-epoxypropyl)-isocyanurate solution obtainedin Step (B) from the solution as a solid, and obtaining atris-(2,3-epoxypropyl)-isocyanurate crystalline body having an increasedcontent ratio of α-type tris-(2,3-epoxypropyl)-isocyanurate from thesolution; and

Step (iii): reacting the tris-(2,3-epoxypropyl)-isocyanurate crystallinebody obtained in Step (i′) with an acid anhydride, provided that a molarratio of (glycidyl groups):(acid anhydrides) is 1:0.05 to 0.5;

as a ninth aspect, the method for manufacturing the modified epoxy resincomposition described in any one of the first to third aspects,comprising Steps (A), (B), (i′), (ii′), and (iii) below:

Step (A): producing an epichlorohydrin adduct of cyanuric acid byreacting 1 mol of cyanuric acid with 5 mol to 180 mol ofepichlorohydrin, and obtaining a solution containingtris-(2,3-epoxypropyl)-isocyanurate by dehydrochlorinating the adduct;

Step (B): adjusting a solid content concentration of the solutioncontaining tris-(2,3-epoxypropyl)-isocyanurate obtained in Step (A) to10% by mass to 50% by mass;

Step (i′): separating β-type tris-(2,3-epoxypropyl)-isocyanuratecontained in the tris-(2,3-epoxypropyl)-isocyanurate solution obtainedin Step (B) from the solution as a solid, and obtaining atris-(2,3-epoxypropyl)-isocyanurate crystalline body having an increasedcontent ratio of α-type tris-(2,3-epoxypropyl)-isocyanurate from thesolution;

Step (ii′): obtaining a tris-(2,3-epoxypropyl)-isocyanurate crystallinebody having a further increased content ratio of α-typetris-(2,3-epoxypropyl)-isocyanurate from the crystalline body obtainedin Step (i′) by extracting β-type tris-(2,3-epoxypropyl)-isocyanuratewith a solvent; and

Step (iii): reacting the tris-(2,3-epoxypropyl)-isocyanurate crystallinebody obtained in Step (ii′) with an acid anhydride, provided that amolar ratio of (glycidyl groups):(acid anhydrides) is 1:0.05 to 0.5;

as a tenth aspect, the manufacturing method described in the ninthaspect, in which the extraction in Step (ii′) is performed with a heatedsolvent;

as an eleventh aspect, the manufacturing method described in any one ofthe eighth to tenth aspects, in which the solvent in thetris-(2,3-epoxypropyl)-isocyanurate solution in Step (i′) isepichlorohydrin; and

as a twelfth aspect, the manufacturing method described in any one ofthe ninth to eleventh aspects, in which the solvent used for extractingβ-type tris-(2,3-epoxypropyl)-isocyanurate in Step (ii′) is methyl ethylketone, acetone, methanol, ethanol, or isopropanol.

Effects of the Invention

The modified epoxy resin composition of the present invention is liquidor solid in a room temperature. The modified epoxy resin composition ishighly stable, and has high solubility and high preservation stability,while retaining heat resistance that is a characteristic of apolyfunctional epoxy resin cured product. The modified epoxy resincomposition of the present invention can be used in fields ofapplications, such as cast molding and transfer molding.

Modes for Carrying Out the Invention

A modified epoxy resin composition of the present invention is amodified epoxy resin composition comprising Compound A containingtris-(2,3-epoxypropyl)-isocyanurate having 1 to 3 glycidyl group(s) in amolecule substituted with a functional group(s) of Formula (1) andCompound B containing tris-(2,3-epoxypropyl)-isocyanurate, in whichtris-(2,3-epoxypropyl)-isocyanurate of Compound A before thesubstitution and tris-(2,3-epoxypropyl)-isocyanurate of Compound Bcomprise 2% by mass to 15% by mass of β-typetris-(2,3-epoxypropyl)-isocyanurate and a remaining percentage of α-typetris-(2,3-epoxypropyl)-isocyanurate based on a total mass oftris-(2,3-epoxypropyl)-isocyanurate of Compound A before thesubstitution and tris-(2,3-epoxypropyl)-isocyanurate of Compound B.

More specifically, a percentage of β-typetris-(2,3-epoxypropyl)-isocyanurate contained intris-(2,3-epoxypropyl)-isocyanurate of Compound A before thesubstitution and tris-(2,3-epoxypropyl)-isocyanurate of Compound B iswithin a range of 2% by mass to 15% by mass, 2% by mass to 10% by mass,3% by mass to 15% by mass, 3% by mass to 10% by mass, or 4% by mass to10% by mass based on a total mass of tris-(2,3-epoxypropyl)-isocyanurateof Compound A before the substitution andtris-(2,3-epoxypropyl)-isocyanurate of Compound B. Accordingly, acontent ratio of α-type tris-(2,3-epoxypropyl)-isocyanurate contained intris-(2,3-epoxypropyl)-isocyanurate of Compound A before thesubstitution and tris-(2,3-epoxypropyl)-isocyanurate of Compound B is98% by mass to 85% by mass, 98% by mass to 90% by mass, 97% by mass to85% by mass, 97% by mass to 90% by mass, or 96% by mass to 90% by massbased on a total mass of tris-(2,3-epoxypropyl)-isocyanurate of CompoundA before the substitution and tris-(2,3-epoxypropyl)-isocyanurate ofCompound B.

The β-type tris-(2,3-epoxypropyl)-isocyanurate herein is a high meltingpoint-type crystal the melting point of which is about 150° C., havingextremely low solubility, and thus a content thereof is preferably 15%by mass or less. A content over 15% by weight is not preferable becausesolubility to a solvent becomes extremely low. Meanwhile, if a contentof β-type tris-(2,3-epoxypropyl)-isocyanurate is too low, that is, lessthan 2% by mass, a melting point becomes high and the solubilitydecreases. That is, highly pure α-bodies induce high crystallinity,which in turn induces not only decrease of a rate of dissolution, butalso decrease of the solubility. In addition, repeated recrystallizationis required in order to remove β-typetris-(2,3-epoxypropyl)-isocyanurate until a content thereof becomes lessthan 2% by mass, which results in low recovery, and thus this method isnot preferable for industrial manufacturing.

Therefore, in the present invention, a content of β-typetris-(2,3-epoxypropyl)-isocyanurate intris-(2,3-epoxypropyl)-isocyanurate having an increased content ratio ofα-type tris-(2,3-epoxypropyl)-isocyanurate of Compound A before thesubstitution and of Compound B, is 2% by weight to 15% by weight basedon a total mass of tris-(2,3-epoxypropyl)-isocyanurate of Compound Abefore the substitution and tris-(2,3-epoxypropyl)-isocyanurate ofCompound B, and is preferably 2% by mass to 10% by mass, and preferably3% by mass to 10% by mass. Preferable ranges from the point of view ofsatisfying both a melting point that is preferred for use and highsolubility are 4% by mass to 10% by mass, 4% by mass to 8% by mass, 2%by mass to 10% by mass, or 2% by mass to 8% by mass.

Preparation of tris-(2,3-epoxypropyl)-isocyanurate used for a modifiedepoxy resin composition of the present invention comprises the steps ofbelow. First, the preparation comprises Step (i), in which separatingβ-type tris-(2,3-epoxypropyl)-isocyanurate contained in atris-(2,3-epoxypropyl)-isocyanurate solution from the solution as asolid, and obtaining a crystalline body having an increased contentratio of α-type tris-(2,3-epoxypropyl)-isocyanurate from the solution.

Specifically, a crystalline body having an increased content ratio ofα-type tris-(2,3-epoxypropyl)-isocyanurate of the present invention canbe obtained by separating β-type tris-(2,3-epoxypropyl)-isocyanurate asa component insoluble to a solvent. Tris-(2,3-epoxypropyl)-isocyanurateusually contains 25% by mass of β-typetris-(2,3-epoxypropyl)-isocyanurate. That is, the crystalline body canbe obtained by dissolving tris-(2,3-epoxypropyl)-isocyanurate whose maincomponent is the α-type in a solvent; filtrating β-typetris-(2,3-epoxypropyl)-isocyanurate that has not been dissolved; andremoving the solvent from the solution.

Although the solvent used herein is not limited, a preferable solventhas high solubility to α-type tris-(2,3-epoxypropyl)-isocyanurate, andhas low solubility to β-type tris-(2,3-epoxypropyl)-isocyanurate. Thatis, a preferable solvent is a solvent in which there is a largedifference between solubility values of both types.

Examples of the solvent include methyl ethyl ketone, acetone,acetonitrile, ethyl acetate, and epichlorohydrin.

Following the description above, the preparation comprises Step (ii), inwhich obtaining a tris-(2,3-epoxypropyl)-isocyanurate crystalline bodyhaving a further increased content ratio of α-typetris-(2,3-epoxypropyl)-isocyanurate from the crystalline body having anincreased content ratio of α-type tris-(2,3-epoxypropyl)-isocyanurateobtained in Step (i) by extracting β-typetris-(2,3-epoxypropyl)-isocyanurate with a solvent.

The extraction in Step (ii) can be performed with a heated solvent.

A temperature for heating the solvent is from a temperature 10° C. ormore higher than a room temperature to a temperature equal to, or lessthan a boiling point of the solvent used at normal pressures.Preferably, the temperature for heating is a temperature around aboiling point of the solvent used at normal pressures.

That is, in Step (ii), a crystalline body having an increased contentratio of α-type tris-(2,3-epoxypropyl)-isocyanurate can be manufacturedby extracting β-type tris-(2,3-epoxypropyl)-isocyanurate with a solventfrom a crystalline body having an increased content ratio of α-typetris-(2,3-epoxypropyl)-isocyanurate containing 15% by mass or less ofβ-type tris-(2,3-epoxypropyl)-isocyanurate obtained by the method ofStep (i). Accordingly, herein, the content ratio of α-typetris-(2,3-epoxypropyl)-isocyanurate can be increased by removing β-typetris-(2,3-epoxypropyl)-isocyanurate by extraction with a solvent havinga smaller difference between the solubility of α-typetris-(2,3-epoxypropyl)-isocyanurate and that of β-typetris-(2,3-epoxypropyl)-isocyanurate.

For example, fractional crystallizing the β-type by using a solventhaving a large difference of about 20:1 between solubility of the α-typeand that of the β-type, such as acetone; and concentrating a filtrate toobtain a crystalline body having a ratio by weight of 94:6 betweenα-type tris-(2,3-epoxypropyl)-isocyanurate and β-typetris-(2,3-epoxypropyl)-isocyanurate. After that, performing solventextraction to the crystal with a solvent such as methyl ethyl ketone,acetone, methanol, ethanol, and isopropanol, particularly heatedmethanol and heated acetone having a smaller difference of about 10:1between the solubility of the α-type and that of the β-type, to obtain acrystalline body having an increased content ratio of α-typetris-(2,3-epoxypropyl)-isocyanurate having a ratio by weight of 96:4between α-type tris-(2,3-epoxypropyl)-isocyanurate and β-typetris-(2,3-epoxypropyl)-isocyanurate.

The crystalline body having an increased content ratio of α-typetris-(2,3-epoxypropyl)-isocyanurate can be obtained also bysimultaneously combining the methods above.

For example, the crystalline body having an increased content ratio ofα-type tris-(2,3-epoxypropyl)-isocyanurate can be obtained by onceextracting α-type tris-(2,3-epoxypropyl)-isocyanurate with a solvent;filtrating β-type tris-(2,3-epoxypropyl)-isocyanurate; concentrating thesolvent of the filtrate to precipitate α-typetris-(2,3-epoxypropyl)-isocyanurate; and filtering crystals. In thiscase, a crystalline body having an increased content ratio of α-typetris-(2,3-epoxypropyl)-isocyanurate containing 2% by weight to 15% byweight of β-type tris-(2,3-epoxypropyl)-isocyanurate can be obtainedmore efficiently, by utilizing the difference of between the solubilityof α-type tris-(2,3-epoxypropyl)-isocyanurate and the solubility ofβ-type tris-(2,3-epoxypropyl)-isocyanurate depending on eachtemperature.

In the present invention, a highly pure α-typetris-(2,3-epoxypropyl)-isocyanurate crystalline body can also be finallymanufactured through steps for manufacturingtris-(2,3-epoxypropyl)-isocyanurate.

That is, the manufacturing comprises Steps (A), (B), and (i′) below:

Step (A): producing an epichlorohydrin adduct of isocyanuric acid byreacting 1 mol of isocyanuric acid with 5 mol to 180 mol ofepichlorohydrin, and obtaining a solution containingtris-(2,3-epoxypropyl)-isocyanurate by dehydrochlorinating the adduct;

Step (B): adjusting a solid content concentration of the solutioncontaining tris-(2,3-epoxypropyl)-isocyanurate obtained in Step (A) to10% by mass to 50% by mass;

Step (i′): separating β-type tris-(2,3-epoxypropyl)-isocyanuratecontained in the tris-(2,3-epoxypropyl)-isocyanurate solution obtainedin Step (B) from the solution as a solid, and obtaining atris-(2,3-epoxypropyl)-isocyanurate crystalline body having an increasedcontent ratio of α-type tris-(2,3-epoxypropyl)-isocyanurate from thesolution.

Following Step (i′), the manufacturing further comprises Step (ii′), inwhich obtaining a crystalline body oftris-(2,3-epoxypropyl)-isocyanurate having a further increased contentratio of α-type tris-(2,3-epoxypropyl)-isocyanurate from the crystallinebody having an increased content ratio of α-typetris-(2,3-epoxypropyl)-isocyanurate obtained in Step (i′) by extractingβ-type tris-(2,3-epoxypropyl)-isocyanurate with a solvent.

The extraction in Step (ii′) can be performed with a heated solvent.

A temperature for heating the solvent is from a temperature 10° C. ormore higher than a room temperature to a temperature equal to, or lessthan a boiling point of the solvent used at normal pressures.Preferably, the temperature for heating is a temperature around aboiling point of the solvent used at normal pressures.

Examples of the solvent used in Step (i′) include epichlorohydrin.Examples of the solvent used in Step (ii′) include methyl ethyl ketone,acetone, methanol, ethanol, and isopropanol.

A modified epoxy resin composition of the present invention is a mixtureof Compound A comprising tris-(2,3-epoxypropyl)-isocyanurate in which aglycidyl group(s) of tris-(2,3-epoxypropyl)-isocyanurate having anincreased content ratio of the α-typetris-(2,3-epoxypropyl)-isocyanurate is(are) substituted with afunctional group(s) of Formula (1) and Compound B comprisingtris-(2,3-epoxypropyl)-isocyanurate having an increased content ratio ofthe α-type tris-(2,3-epoxypropyl)-isocyanurate.

In a modified epoxy resin composition of the present invention, a molarratio of Compound A:Compound B can be 90:10 to 30:70.

Compound A is a mixture of a compound in which one acid anhydride ofFormula (2) below is added to a glycidyl group oftris-(2,3-epoxypropyl)-isocyanurate having an increased content ratio ofα-type tris-(2,3-epoxypropyl)-isocyanurate; a compound in which two acidanhydrides of Formula (2) below is added to glycidyl groups oftris-(2,3-epoxypropyl)-isocyanurate having an increased content ratio ofα-type tris-(2,3-epoxypropyl)-isocyanurate; and a compound in whichthree acid anhydrides of Formula (2) below is added to glycidyl groupsof tris-(2,3-epoxypropyl)-isocyanurate having an increased content ratioof α-type tris-(2,3-epoxypropyl)-isocyanurate.

The modified epoxy resin composition of the present invention can beobtained by reacting glycidyl groups intris-(2,3-epoxypropyl)-isocyanurate having an increased content ratio ofα-type tris-(2,3-epoxypropyl)-isocyanurate with acid anhydrides with amolar ratio of 1:0.05 to 0.5.

Compound A preferably remains as the mixture of a compound in which oneacid anhydride of Formula (2) below is added to a glycidyl group oftris-(2,3-epoxypropyl)-isocyanurate; a compound in which two acidanhydrides of Formula (2) below are added to glycidyl groups oftris-(2,3-epoxypropyl)-isocyanurate; and a compound in which three acidanhydrides of Formula (2) below are added to glycidyl groups oftris-(2,3-epoxypropyl)-isocyanurate.

That is, the modified epoxy resin composition of the present inventionis preferably manufactured by reacting thetris-(2,3-epoxypropyl)-isocyanurate crystalline body obtained in Step(i′), Step (ii), or (ii′) with an acid anhydride, provided that a molarratio of glycidyl groups of tris-(2,3-epoxypropyl)-isocyanurate:acidanhydrides is 1:0.05 to 0.5, as Step (iii). It is preferable that themodified epoxy resin composition containing a mixture (Compound A) of acompound in which one acid anhydride of Formula (2) below is added to aglycidyl group of tris-(2,3-epoxypropyl)-isocyanurate; a compound inwhich two acid anhydrides of Formula (2) below are added to glycidylgroups of tris-(2,3-epoxypropyl)-isocyanurate; and a compound in whichthree acid anhydrides of Formula (2) below are added to glycidyl groupsof tris-(2,3-epoxypropyl)-isocyanurate andtris-(2,3-epoxypropyl)-isocyanurate (Compound B) with a molar ratio of90:10 to 30:70 for (Compound A):(Compound B) is obtained.

Here, the acid anhydride [Formula (2)] used for manufacturing a modifiedepoxy resin composition of the present invention is what is called anacid anhydride obtained from two molecules of a monocarboxylic acid, andthis acid anhydride does not function as a curing agent of epoxy resins,unlike an acid anhydride that is obtained from a dicarboxylic acid andis used as a curing agent of epoxy resins.

(wherein, R¹ and R² have the same meaning as those in Formula (1).)

The average total number of glycidyl groups in synthesized Compound Aand glycidyl groups in Compound B is preferably two or more in terms ofone molecule (dividing the total number of glycidyl groups by the totalnumber of molecules). The number of less than two is not preferablebecause physical properties of cured products, particularly heatresistance, are decreased.

Although the acid anhydride [Formula (2)] used in the present inventionis not particularly limited, R¹ and R² are each independently an alkylgroup, an alkenyl group, an alkynyl group, an aryl group, an aralkylgroup, a heterocyclic group; or a halogenated derivative group, anaminated derivative group, or a nitrated derivative group thereof.Examples of the alkyl group include C₁₋₁₈ alkyl groups such as methylgroup, ethyl group, n-propyl group, isopropyl group, n-butyl group,isobutyl group, t-butyl group, n-heptyl group, and cyclohexyl group.Examples of the alkenyl group include C₂₋₆ alkenyl groups such as vinylgroup, 1-propenyl group, and 2-propenyl group. Examples of the alkynylgroup include C₂₋₆ alkynyl groups such as ethynyl group and propargylgroup. Examples of the aryl group include C₆₋₂₀ aryl groups such asphenyl group, tolyl group, naphthyl group, methylnaphthyl group, anthrylgroup, and ethylanthryl group. Examples of the aralkyl group includeC₇₋₂₂ aralkyl groups such as benzyl group, phenethyl group,naphthylmethyl group, naphthylethyl group, anthryl group, andanthrylmethyl group. Examples of the heterocyclic group includeimidazole group, pyrazole group, pyridazine group, pyrimidine group,quinoline group, benzoxazol group, thiophene group, dithiol group,thiazole group, thiadiazole group, and benzothiazole group. Each ofthese groups including an alkyl group, an alkenyl group, an alkynylgroup, an aryl group, an aralkyl group, and a heterocyclic group can beused as a halogenated (fluorinated, chlorinated, brominated, oriodinated) derivative group, an aminated derivative group, or a nitratedderivative group. Examples thereof include chloromethyl group,dichloromethyl group, trichloromethyl group, trifluoromethyl group,aminophenyl group, and nitrobenzyl group. R¹ and R² may be same ordifferent. Note that the examples of R¹ and R² in Formula (2) are alsoexamples of R¹ and R² in Formula (1), in which R¹ and R² in Formula (1)are functional groups whereby tris-(2,3-epoxypropyl)-isocyanurate issubstituted.

Examples of the acid anhydride of Formula (2) containing R¹ and R²include acetic anhydride, propionic anhydride, n-butyric anhydride,n-valeric anhydride, n-hexanoic anhydride, and trifluoroaceticanhydride. R¹ and R² in Formula (1) are determined depending on the acidanhydride [Formula (2)], and the R¹ and R² are each preferably a C₁₋₅hydrocarbon group.

Next, the reaction between tris-(2,3-epoxypropyl)-isocyanurate and anacid anhydride will be explained in more detail.

A solvent used in the reaction only needs to be inactive to thereaction. Representative examples of the solvent include ketones, suchas acetone and methyl ethyl ketone; nitriles, such as acetonitrile;ethers, such as tetrahydrofuran and dioxane; esters, such as ethylacetate; aromatic hydrocarbons, such as chlorobenzene and toluene; andhalogenated hydrocarbons, such as chloroform and dichloroethane. Thesesolvents can be used singly, or can be used as a mixed solvent thereofto dissolve tris-(2,3-epoxypropyl)-isocyanurate. If necessary, atertiary amine, such as triethylamine, tripropylamine, and1,8-diazabicyclo-5,4,0-undecan-7-ene; a quaternary phosphonium salt,such as a halogenated triphenyl monoalkyl phosphonium represented bytriphenylethylphosphonium bromide and the like; an imidazole compound,such as 2-ethyl-4-methyl imidazole; a quaternary ammonium salt, such astetraethylammonium bromide; or a phosphorus compound, such astriphenylphosphine can be used as a catalyst.

The reaction temperature is from 60° C. to the reflux temperature of asolvent, and the reaction continues until the peak of an added acidanhydride disappears as determined by a GC analysis. After the reactionis ended, the solvent is distilled away to obtain a modified epoxy resincomposition.

The result of a GC analysis showed that the obtained modified epoxyresin composition contained a mixture of a compound in which one acidanhydride of Formula (2) below is added to a glycidyl group oftris-(2,3-epoxypropyl)-isocyanurate; a compound in which two acidanhydrides of Formula (2) below are added to glycidyl groups oftris-(2,3-epoxypropyl)-isocyanurate; and a compound in which three acidanhydrides of Formula (2) below are added to glycidyl groups oftris-(2,3-epoxypropyl)-isocyanurate (Compound A) and unreactedtris-(2,3-epoxypropyl)-isocyanurate (Compound B).

Unlike the case where a monocarboxylic acid is added to an epoxy resin,hydroxy group generated by ring-opening of an epoxy group does not existin the present invention, and thus gelation does not occur even if thepresent invention is stored after being mixed with an acid anhydridecuring agent. In contrast, there has been a problem, that is, hydroxygroup, which is generated by ring-opening of an epoxy group that ispartially modified with a monocarboxylic acid, facilitates a reactionwhen trying to obtain a cured product by using an acid anhydride curingagent, and thus gelation cannot be prevented even if a composition isstored after dissolving it in an acid anhydride curing agent. Inaddition, unlike an dicarboxylic acid anhydride that is usually used asa curing agent of epoxy resins, an acid anhydride of a modified compoundused in the present invention is modifiedtris-(2,3-epoxypropyl)-isocyanurate after reaction withtris-(2,3-epoxypropyl)-isocyanurate, and thus it is not reacted duringstorage, not reacted or gelated upon heating.

In addition, advantages to use tris-(2,3-epoxypropyl)-isocyanurate as anepoxy resin having high crystallinity are that thetris-(2,3-epoxypropyl)-isocyanurate gives a cured product that is notonly heat resistant, but also weather resistant, light resistant, andhighly transparent. That is, because tris-(2,3-epoxypropyl)-isocyanuratehas a triazine backbone, UV absorption is small, and oxidativedecomposition does not easily occur in thetris-(2,3-epoxypropyl)-isocyanurate compared to many epoxy resins havingaromatic rings, and thus the cured product is colored little by UVirradiation, and is highly transparent.

Also, because glycidyl group is partially modified, characteristics suchas water absorbability and mechanical strength, which are disadvantagesof polyfunctional epoxy cured products, are improved. That is, a curedproduct utilizing a modified epoxy resin composition of the presentinvention has low water absorbability, and high mechanical strengthwhile keeping high heat resistance.

If necessary, the modified epoxy resin composition of the presentinvention can be used by mixing with a liquid acid anhydride curingagent, and dissolving the composition in the agent. The liquid acidanhydride used herein is an acid anhydride usually used as a curingagent for epoxy resins. As the liquid acid anhydride, for example, atleast one selected from the group consisting of methyl himic acidanhydride, methyl hexahydro phthalic acid anhydride, and methyltetrahydro phthalic acid anhydride is used, and the anhydride can beused singly, or as a combination of two or more of them.

The modified epoxy resin composition of the present invention can beused as dissolved in a commercially available epoxy resin that is liquidat a room temperature. Although any mixing ratio can be taken, when amodified epoxy resin composition of the present invention is 100 partsby weight, a liquid epoxy resin is preferably 100 parts by weight orless. If the liquid epoxy resin is over 100 parts by weight,characteristics which the modified epoxy resin composition of thepresent invention inherently has become weak. Although the epoxy resinthat is liquid at a room temperature used herein is not particularlylimited, examples thereof include a bisphenol-A-type liquid epoxy resin,a bisphenol-F-type liquid epoxy resin, a hexahydro bisphenol-A-typeliquid epoxy resin, and a dimer acid diglycidyl ester.

A curing agent that is usually used for epoxy resins can be used as acuring agent for curing a modified epoxy resin composition of thepresent invention. Examples thereof include phenol resins, such asphenol novolac resins and cresol novolac resins; acid anhydrides, suchas methyl himic acid anhydride, methyl hexahydro phthalic acidanhydride, hexahydro phthalic acid anhydride, methyl tetrahydro phthalicacid anhydride, tetrahydro phthalic acid anhydride, and pyromelliticacid anhydride; and amines, such as diethylenetriamine,isophoronediamine, diaminodiphenylmethane, and diaminodiphenylsulfone.

Also, when obtaining the cured product described above, a curingaccelerator can suitably be combined. Examples of the curing acceleratorinclude imidazoles, such as 2-methyl imidazole and 2-ethyl-4 methylimidazole; amines, such as 2,4,6-tris(dimethylaminomethyl)phenol andbenzyldimethylamine; organophosphorus compounds, such astriphenylphosphine and tributylphosphine; and quaternary phosphoniumsalts, such as halogenated triphenyl monoalkyl phosphoniums representedby triphenylethylphosphonium bromide and the like.

EXAMPLES

The following are devices used for analyzing samples.

HPLC

Device: LC-20A system manufactured by SHIMADZU Corporation (analysis ofcompositions of α-type and β-type)

GC

Device: GC-2010 system manufactured by SHIMADZU Corporation (analysis ofcompositions after modifications)

Viscosity measurement: E-type viscometer (VISCONIC ED) manufactured byTOKIMEC INC.

Transmittance measurement: UV-Vis-NIR spectrophotometer (UV-3600)manufactured by SHIMADZU Corporation

Bending test: Precision universal tester (AGS-X series) manufactured bySHIMADZU Corporation

Coefficient of linear expansion, glass transition temperaturemeasurement: Thermomechanical analyzer (TMA Q400) manufactured by TAInstruments

<Method for Measuring Proportion of α-type and β-type ofTris-(2,3-epoxypropyl)-isocyanurate>

HPLC was performed by using a commercially available column for opticalresolution whose product name is CHIRALPAK AS-3 (manufactured by DaicelCorporation (0.46 cm diameter×10 cm long)) and n-hexane/ethanol (60/40w/w) as an eluant, in the condition of 40° C. for a column temperatureand 0.4 ml/minute for flux. The crystals in a sample were dissolved inacetonitrile, and the solution was further diluted with the eluant. Thediluted solution was injected into HPLC to be separated bychromatography. The β-type tris-(2,3-epoxypropyl)-isocyanurate is elutedat 11.1 minutes and 13.2 minutes; and the α-typetris-(2,3-epoxypropyl)-isocyanurate is eluted at 11.7 minutes and 12.4minutes. The proportion of α-type or β-type in the total crystals wascalculated by the area ratio of each of the peaks.

<Method for Measuring Proportion of Tris-(2,3-epoxypropyl)-isocyanurateand Modified Product Thereof>

GC was performed by using a commercially available column whose productname is HP-5 (manufactured by Agilent Technologies, Inc.) (30 m×0.32mm×0.25 μm), in the condition of 250° C. for an injector temperature,300° C. for a detector temperature, 40° C. (5 minutes) −>20° C./minute−>300° C. (12 minutes) for oven temperatures, a carrier gas: nitrogen,89.1 kPa for gas pressure, 74.4 ml/minute for total flux, 3.4 ml/minutefor column flux, and 50 cm/second for linear velocity. Samples weredissolved in acetonitrile for measurements.Tris-(2,3-epoxypropyl)-isocyanurate was detected at 16.5 minutes, oneadduct of propionic anhydride to tris-(2,3-epoxypropyl)-isocyanurate wasdetected at 18.4 minutes, two adducts of propionic anhydride totris-(2,3-epoxypropyl)-isocyanurate were detected at 20.9 minutes, andthree adducts of propionic anhydride totris-(2,3-epoxypropyl)-isocyanurate were detected at 25.1 minutes. Theproportion of tris-(2,3-epoxypropyl)-isocyanurate and each of themodified products thereof was calculated by the area ratio of each ofthe peaks.

Synthesis Example 1

To a reaction flask having an inner volume of 2 liters and equipped witha stirrer, 30 g of water, 5.5 g of tetramethylammonium chloride, 1,388 g(15 mol) of epichlorohydrin, and 129 g (1 mol) of isocyanuric acid wereplaced to form a reaction mixture. Next, the reaction mixture in theflask was heated with stirring to elevate a temperature. When thetemperature of the reaction mixture reached 89° C., the reaction mixturestarted to be boiled under atmospheric pressure; however, the reactionmixture was continued to be heated. Generated steam was cooled in acondenser, all of liquefied epichlorohydrin was sequentially refluxed inthe flask, and liquefied water was discharged out of the flask. Theseprocesses were performed to be continued for five hours to allow thetemperature of the reaction mixture to reach 120° C. Then heating wasstopped at this time point, and the reaction mixture was cooled toobtain a reaction product whose temperature was 45° C. Unreactedisocyanuric acid was not detected in this product.

Next, as the entire reaction product in the flask was kept at 50° C.,dropping of 256 g (3.2 mol as NaOH) of a 50% by mass sodium hydroxideaqueous solution to the reaction product was started under 100 mmHg ofreduced pressure to form a reaction mixture. At the same time, water andepichlorohydrin were allowed to be evaporated from the reaction mixturewith stirring vigorously. As gradually increasing the degree of reducedpressure, steam was cooled in a condenser, all of liquefiedepichlorohydrin was sequentially refluxed in the flask, and liquefiedwater was discharged out of the flask. As continuing these processes,dropping was stopped when the degree of reduced pressure reached 60 mmHgto obtain slurry containing precipitated sodium chloride. Six hours havepassed from the beginning to ending of the dropping. During the sixhours, the stirred reaction mixture was kept homogeneous, while itbecame clouded by precipitated sodium chloride. According to a liquidchromatography analysis, a content of the compound having a2-hydroxy-3-chlorpropyl group in the obtained slurry was 1% or less.

The obtained tris-(2,3-epoxypropyl)-isocyanurate was (in crystallinebodies, the mass ratio of α crystals:β crystals=75:25).

Synthesis Example 2

80.0 kg (269 mol) of the highly pure tris-(2,3-epoxypropyl)-isocyanuratemanufactured in Synthesis Example 1 and 680 kg of acetone were mixed,and stirred at 9° C. After that, crystals were filtered to obtain afiltrate containing a high proportion of the α-type. The filtrate wasvacuum concentrated at 40° C., 243 kg of methanol was added thereto, andthe mixture was cooled to 20° C. After that, the mixture was filtered,and the obtained crystals were vacuum dried to obtain 37.3 kg (125 mol)of tris-(2,3-epoxypropyl)-isocyanurate (in crystalline bodies, the massratio of α crystals:β crystals=98:2).

Synthesis Example 3

5.0 g (17 mmol) of the highly pure tris-(2,3-epoxypropyl)-isocyanuratemanufactured in Synthesis Example 1 and 42.5 g of epichlorohydrin weremixed, and stirred at 6° C. After that, crystals were filtered to obtaina filtrate containing a high proportion of the α-type. 785 g of methanolwas added thereto, and the mixture was cooled to −78° C. After that, themixture was filtered, and the obtained crystals were vacuum dried toobtain 3.2 g (11 mmol) of tris-(2,3-epoxypropyl)-isocyanurate (incrystalline bodies, the mass ratio of α crystals:β crystals=92:8).

Synthesis Example 4

42.5 g of tris-(2,3-epoxypropyl)-isocyanurate (the mass ratio of αcrystals:β crystals=98:2) manufactured in Synthesis Example 2, 11.0 g ofacetonitrile, 7.63 g (the molar ratio of glycidyl groups:acidanhydrides=1:0.13) of propionic anhydride, and 23.8 mg of ethyl triethylphosphonium bromide were mixed, and stirred at 100° C. for 2 hours.After that, the mixture was vacuum concentrated to obtain 47.8 g of aliquid modified epoxy resin composition.

As a result of a GC analysis, a molar ratio of one adduct of propionicanhydride to tris-(2,3-epoxypropyl)-isocyanurate, two adducts ofpropionic anhydride to tris-(2,3-epoxypropyl)-isocyanurate, threeadducts of propionic anhydride to tris-(2,3-epoxypropyl)-isocyanurate,and tris-(2,3-epoxypropyl)-isocyanurate (non-adduct) in the product was39.7:8.1:0.4:51.8 (a molar ratio of Compound A:Compound B=48.2:51.8).The epoxy equivalent was 138.1 g/eq, viscosity was 4, 090 mPa·s at 60°C. This epoxy resin composition was designated as (i-1).

Synthesis Example 5

42.5 g of tris-(2,3-epoxypropyl)-isocyanurate (the mass ratio of αcrystals:β crystals=98:2) manufactured in Synthesis Example 2, 11.0 g ofacetonitrile, 11.2 g (the molar ratio of glycidyl groups:acidanhydrides=1:0.20) of propionic anhydride, and 23.8 mg of ethyl triethylphosphonium bromide were mixed, and stirred at 100° C. for 4 hours.After that, the mixture was vacuum concentrated to obtain 52.4 g of aliquid modified epoxy resin composition.

As a result of a GC analysis, a molar ratio of one adduct of propionicanhydride to tris-(2,3-epoxypropyl)-isocyanurate, two adducts ofpropionic anhydride to tris-(2,3-epoxypropyl)-isocyanurate, threeadducts of propionic anhydride to tris-(2,3-epoxypropyl)-isocyanurate,and tris-(2,3-epoxypropyl)-isocyanurate (non-adduct) in the product was46.0:14.5:1.3:38.2 (a molar ratio of Compound A:Compound B=61.8:38.2).The epoxy equivalent was 157.2 g/eq, viscosity was 3,344 mPa·s at 60° C.This epoxy resin composition was designated as (i-2).

Synthesis Example 6

85.0 g of tris-(2,3-epoxypropyl)-isocyanurate (the mass ratio of αcrystals:β crystals=98:2) manufactured in Synthesis Example 2, 46.8 g oftoluene, 29.8 g (the molar ratio of glycidyl groups:acidanhydrides=1:0.27) of propionic anhydride, and 48.6 mg of ethyl triethylphosphonium bromide were mixed, and stirred at 100° C. for 8 hours, and120° C. for 3 hours. After that, the mixture was vacuum concentrated toobtain 112.8 g of a liquid modified epoxy resin composition.

As a result of a GC analysis, a molar ratio of one adduct of propionicanhydride to tris-(2,3-epoxypropyl)-isocyanurate, two adducts ofpropionic anhydride to tris-(2,3-epoxypropyl)-isocyanurate, threeadducts of propionic anhydride to tris-(2,3-epoxypropyl)-isocyanurate,and tris-(2,3-epoxypropyl)-isocyanurate (non-adduct) in the product was52.5:22.3:2.2:23.1 (a molar ratio of Compound A:Compound B=76.9:23.1).The epoxy equivalent was 177.4 g/eq, viscosity was 2,610 mPa·s at 60° C.This epoxy resin composition was designated as (i-3).

Synthesis Example 7

2.70 g of tris-(2,3-epoxypropyl)-isocyanurate (the mass ratio of αcrystals:β crystals=92:8) manufactured in Synthesis Example 3, 0.71 g ofacetonitrile, 0.49 g (the molar ratio of glycidyl groups:acidanhydrides=1:0.13) of propionic anhydride, and 1.5 mg of ethyl triethylphosphonium bromide were mixed, and stirred at 110° C. for 6 hours.After that, the mixture was vacuum concentrated to obtain 2.97 g of aliquid modified epoxy resin composition.

As a result of a GC analysis, a molar ratio of one adduct of propionicanhydride to tris-(2,3-epoxypropyl)-isocyanurate, two adducts ofpropionic anhydride to tris-(2,3-epoxypropyl)-isocyanurate, threeadducts of propionic anhydride to tris-(2,3-epoxypropyl)-isocyanurate,and tris-(2,3-epoxypropyl)-isocyanurate (non-adduct) in the product was40.2:5.0:0.2:54.6 (a molar ratio of Compound A:Compound B=45.4:54.6).The epoxy equivalent was 134.4 g/eq, viscosity was 4, 280 mPa·s at 60°C. This epoxy resin composition was designated as (i-4).

Reference Example 1

42.5 g of tris-(2,3-epoxypropyl)-isocyanurate (the mass ratio ofα-types:β-types=75:25) manufactured in Synthesis Example 1, 11.0 g ofacetonitrile, 7.63 g (the molar ratio of glycidyl groups:acidanhydrides=1:0.13) of propionic anhydride, and 23.8 mg of ethyl triethylphosphonium bromide were mixed, and stirred at 100° C. for 2 hours.After that, the mixture was vacuum concentrated to obtain 48.3 g of aliquid modified epoxy resin composition.

As a result of a GC analysis, a molar ratio of one adduct of propionicanhydride to tris-(2,3-epoxypropyl)-isocyanurate, two adducts ofpropionic anhydride to tris-(2,3-epoxypropyl)-isocyanurate, threeadducts of propionic anhydride to tris-(2,3-epoxypropyl)-isocyanurate,and tris-(2,3-epoxypropyl)-isocyanurate (non-adduct) in the product was37.7:7.9:0.6:53.8 (a molar ratio of Compound A:Compound B=46.2:53.8).The epoxy equivalent was 136.4 g/eq, viscosity was 4, 640 mPa·s at 60°C. This epoxy resin composition was designated as (i-5).

Reference Example 2

42.5 g of tris-(2,3-epoxypropyl)-isocyanurate (the mass ratio ofα-types:β-types=75:25) manufactured in Synthesis Example 1, 11.0 g ofacetonitrile, 11.2 g (the molar ratio of glycidyl groups:acidanhydrides=1:0.20) of propionic anhydride, and 23.8 mg of ethyl triethylphosphonium bromide were mixed, and stirred at 100° C. for 4 hours.After that, the mixture was vacuum concentrated to obtain 52.1 g of aliquid modified epoxy resin composition.

As a result of a GC analysis, a molar ratio of one adduct of propionicanhydride to tris-(2,3-epoxypropyl)-isocyanurate, two adducts ofpropionic anhydride to tris-(2,3-epoxypropyl)-isocyanurate, threeadducts of propionic anhydride to tris-(2,3-epoxypropyl)-isocyanurate,and tris-(2,3-epoxypropyl)-isocyanurate (non-adduct) in the product was45.2:14.3:1.5:39.1 (a molar ratio of Compound A:Compound B=60.9:39.1).The epoxy equivalent was 157.9 g/eq, viscosity was 3,748 mPa·s at 60° C.This epoxy resin composition was designated as (i-6).

Reference Example 3

85.0 g of tris-(2,3-epoxypropyl)-isocyanurate (the mass ratio ofα-types:β-types=75:25) manufactured in Synthesis Example 1, 46.8 g oftoluene, 29.8 g (the molar ratio of glycidyl groups:acidanhydrides=1:0.27) of propionic anhydride, and 48.6 mg of ethyl triethylphosphonium bromide were mixed, and stirred at 100° C. for 8 hours and120° C. for 1 hour. After that, the mixture was vacuum concentrated toobtain 113.3 g of a liquid modified epoxy resin composition.

As a result of a GC analysis, a molar ratio of one adduct of propionicanhydride to tris-(2,3-epoxypropyl)-isocyanurate, two adducts ofpropionic anhydride to tris-(2,3-epoxypropyl)-isocyanurate, threeadducts of propionic anhydride to tris-(2,3-epoxypropyl)-isocyanurate,and tris-(2,3-epoxypropyl)-isocyanurate (non-adduct) in the product was51.0:22.9:2.6:23.5 (a molar ratio of Compound A:Compound B=76.5:23.5).The epoxy equivalent was 181.8 g/eq, viscosity was 2,681 mPa·s at 60° C.This epoxy resin composition was designated as (i-7).

(Solubility Test to Solvent)

To 100 g of each of the solvents, each of the epoxy resin compositionswas added with each of the amounts shown below, and the mixtures wereleft at 25° C. for 1 week or longer. After that, the mixtures werevisually inspected for existence of precipitated crystals. The resultsare shown in Tables 1 to 5, as the case where none of crystals wereobserved is (∘), and the case where crystals were precipitated is (×).Note that (−) means that the solubility test was not conducted. InTables, PGME refers to propylene glycol monomethyl ether, PGMEA refersto propylene glycol monomethyl ether acetate, and MEK refers to methylethyl ketone.

TABLE 1 Example 1 Example 2 Example 3 Example 4 Example 5 Amount ofEpoxy Resin Composition Epoxy Resin (i-1) (i-1) (i-1) (i-1) (i-1)Composition Solvent (g/solvent Ethyl 100 g) PGME PGMEA MEK AcetateToluene 25 — x — — — 20 — x x x — 15 x ∘ ∘ x — 10 ∘ ∘ ∘ ∘ x 5 ∘ ∘ — — x3 — — — — ∘ 1 — — — — —

TABLE 2 Exam- Exam- Exam- Exam- Exam- ple 6 ple 7 ple 8 ple 9 ple 10Amount of Epoxy Resin Composition Epoxy Resin (i-4) (i-4) (i-4) (i-4)(i-4) Composition Solvent (g/solvent Ethyl 100 g) PGME PGMEA MEK AcetateToluene 20 x x x x — 10 x ∘ ∘ x x 5 ∘ ∘ ∘ ∘ — 3 — — — — x 1 — — — — ∘

TABLE 3 Compar- Compar- Compar- Compar- Compar- ative ative ative ativeative Example 1 Example 2 Example 3 Example 4 Example 5 Amount of EpoxyResin Composition Epoxy Resin (i-5) (i-5) (i-5) (i-5) (i-5) CompositionSolvent (g/solvent Ethyl 100 g) PGME PGMEA MEK Acetate Toluene 10 x x xx x 5 x x x x x 3 ∘ ∘ x x x 1 ∘ ∘ x x x

TABLE 4 Exam- Exam- Exam- Exam- Exam- ple 11 ple 12 ple 13 ple 14 ple 15Amount of Epoxy Resin Composition Epoxy Resin (i-3) (i-3) (i-3) (i-3)(i-3) Composition Solvent (g/solvent Ethyl 100 g) PGME PGMEA MEK AcetateToluene 40 — x x x — 35 — x ∘ x — 30 x ∘ ∘ ∘ — 25 x ∘ ∘ ∘ — 20 x ∘ ∘ ∘ x15 x — — — x 10 ∘ — — — ∘ 5 — — — — ∘

TABLE 5 Compar- Compar- Compar- Compar- Compar- ative ative ative ativeative Exam- Exam- Exam- Exam- Exam- ple 6 ple 7 ple 8 ple 9 ple 10Amount of Epoxy Resin Composition Epoxy Resin (i-7) (i-7) (i-7) (i-7)(i-7) Composition Solvent (g/solvent Ethyl 100 g) PGME PGMEA MEK AcetateToluene 25 — — x — — 20 x x ∘ x — 15 x x ∘ x — 10 x ∘ ∘ ∘ x 5 ∘ — — — x3 — — — — ∘

In the epoxy resin composition (i-3) in whichtris-(2,3-epoxypropyl)-isocyanurate having the mass ratio ofα-types:β-types=97:3 was modified, solubility was improved in any of thesolvents compared to the epoxy resin composition (i-7) in whichtris-(2,3-epoxypropyl)-isocyanurate having the mass ratio ofα-types:β-types=75:25 was modified.

(Solubility Test to Acid Anhydride as Curing Agent)

Example 16

To 4.0 g of the epoxy resin composition (i-1), 4.8 g of a compoundhaving the product name of RIKACID MH-700 (manufactured by New JapanChemical Co., Ltd., a liquid mixture containinghexahydro-4-methylphthalic anhydride and hexahydro phthalic anhydride inthe mass ratio of 70/30) was added, and mixed and defoamed in a devicefor stirring and defoaming (the product name: Awatori Rentaro,manufactured by THINKY Corporation) to prepare a composition.Ingredients were confirmed to be colorless and transparent, and to bedissolved uniformly. After that, the composition was left at 25° C. for40 days, and then the appearance of the composition was visuallyconfirmed.

Example 17

To 0.40 g of the epoxy resin composition (i-4), 0.48 g of a compoundhaving the product name of RIKACID MH-700 (manufactured by New JapanChemical Co., Ltd., a liquid mixture containinghexahydro-4-methylphthalic anhydride and hexahydro phthalic anhydride inthe mass ratio of 70/30) was added, and mixed and defoamed in a devicefor stirring and defoaming (the product name: Awatori Rentaro,manufactured by THINKY Corporation) to prepare a composition.Ingredients were confirmed to be colorless and transparent, and to bedissolved uniformly. After that, the composition was left at 25° C. for1 week, and then the appearance of the composition was visuallyconfirmed.

Comparative Example 11

To 4.0 g of the epoxy resin composition (i-5), 4.8 g of a compoundhaving the product name of RIKACID MH-700 (manufactured by New JapanChemical Co., Ltd., a liquid mixture containinghexahydro-4-methylphthalic anhydride and hexahydro phthalic anhydride inthe mass ratio of 70/30) was added, and mixed and defoamed in a devicefor stirring and defoaming (the product name: Awatori Rentaro,manufactured by THINKY Corporation) to prepare a composition.Ingredients were confirmed to be colorless and transparent, and to bedissolved uniformly. After that, the composition was left at 25° C. for40 days, and then the appearance of the composition was visuallyconfirmed.

TABLE 6 Comparative Example 16 Example 17 Example 11 Epoxy ResinComposition (i-1) (i-4) (i-5) Curing Agent MH-700 MH-700 MH-700Appearance Colorless and Colorless and Clouded Transparent Transparent

The epoxy resin composition (i-1) in whichtris-(2,3-epoxypropyl)-isocyanurate having the mass ratio ofα-types:β-types=97:3 was modified and the epoxy resin composition (i-4)in which tris-(2,3-epoxypropyl)-isocyanurate having the mass ratio ofα-types:β-types=92:8 was modified were uniformly dissolved in curingagents after they were left; however, in the epoxy resin composition(i-5) in which tris-(2,3-epoxypropyl)-isocyanurate having the mass ratioof α-types:β-types=75:25 was modified, crystals were precipitated andthe solution became clouded because of low solubility of the epoxy resincomposition (i-5).

[Preparation of Heat Cured Product]

Example 18

To 20.0 g of the epoxy resin composition (i-1), 23.9 g of an acidanhydride curing agent RIKACID MH700 (the product name, manufactured byNew Japan Chemical Co., Ltd., the ingredient is a mixture in whichhexahydro-4-methylphthalic anhydride and hexahydro phthalic anhydrideare mixed in the molar ratio of 70:30) and 0.2 g of a curing acceleratorHISHICOLIN PX-4ET (the product name, manufactured by The NipponSynthetic Chemical Industry Co., Ltd., the ingredient istetrabutylphosphonium diethyl phosphorodithioate) were added, and mixedand defoamed in a device for stirring and defoaming (the product name:Awatori Rentaro, manufactured by THINKY Corporation) to prepare acomposition.

The mixture was poured between glass plates sandwiching a 3 mm siliconerubber, in which the glass plates were treated with a releasing agent(the treatment was performed at 150° C. for 1 hour with the releasingagent SR-2410 (the product name) manufactured by Dow Corning Toray Co.,Ltd.), and curing was performed such that preliminary curing wasperformed at 100° C. for 2 hours, and actual curing was performed at150° C. for 5 hours.

Example 19

20.0 g of the epoxy resin composition (i-2), 21.0 g of RIKACID MH-700,and 0.20 g of HISHICOLIN PX-4ET were placed in the same manner as in thecase of Example 18, and curing was performed.

Example 20

20.0 g of the epoxy resin composition (i-3), 18.6 g of RIKACID MH-700,and 0.20 g of HISHICOLIN PX-4ET were placed in the same manner as in thecase of Example 18, and curing was performed.

Comparative Example 12

20.0 g of the epoxy resin composition (i-5), 24.2 g of RIKACID MH-700,and 0.20 g of HISHICOLIN PX-4ET were placed in the same manner as in thecase of Example 18, and curing was performed.

Comparative Example 13

20.0 g of the epoxy resin composition (i-6), 20.9 g of RIKACID MH-700,and 0.20 g of HISHICOLIN PX-4ET were placed in the same manner as in thecase of Example 18, and curing was performed.

Comparative Example 14

20.0 g of the epoxy resin composition (i-7), 18.1 g of RIKACID MH-700,and 0.20 g of HISHICOLIN PX-4ET were placed in the same manner as in thecase of Example 18, and curing was performed.

For the obtained cured product, a three-point bending test (bendingstrength and bending modulus of elasticity) was conducted, andtransmittance, a glass transition temperature, and a coefficient oflinear expansion of the product were measured.

(Measurement of Bending Property)

Bending Properties were measured with a universal testing machineaccording to JIS K-6911.

The height and width of a test piece were measured, and the test piecewas supported. Loads were applied on the center of the test piece with apressure wedge, and a load by which the test piece was broken wasmeasured to calculate a bending strength (σ).

A bending strength σ: (MPa) {kgf/mm²}; P: a load when the test piece wasbroken (N) {kgf}; L: a distance between fulcra (mm); W: a width of thetest piece (mm); and h: a height of the test piece (mm).σ=(3PL)/(2Wh ²)

When F/Y is a slope on a linear portion on a load-deflection curve(N/mm) {kgf/mm}, bending modulus of elasticity (E): (MPa) {kgf/mm²} isE=[L ³/(4Wh ³)]×[FLY]

(Measurement of Transmittance)

Transmittance at 400 nm was measured by using a spectrophotometer.

(Measurement of Glass Transition Temperature (Tg))

A thickness of the test piece was precisely measured, and an expansionand contraction method of TMA (thermo-mechanical analysis) was performedwith a load of 0.05 N and a rate of temperature rise at 5° C./minute.Tangent lines were drawn on a curve before and after a glass transitionpoint, and Tg was calculated from a intersecting point of the tangentlines.

(Measurement of Coefficient of Linear Expansion)

The coefficient of linear expansion was measured according to JISK-6911. A thickness of the test piece was precisely measured, and anexpansion and contraction method of TMA (thermo-mechanical analysis) wasperformed with a load of 0.05 N and a rate of temperature rise at 5°C./minute.

The linear coefficient of expansion α1 was calculated as: an amount ofchange of the length from at 30° C. to at 80° C. (ΔL1)/an initial lengthof the test piece (L)×50=α1.

TABLE 7 Bending Coefficient Bending Modulus of Transmit- of LinearStrength Elasticity tance Tg Expansion MPa MPa % ° C. ppm/° C. Example18 145 3778 90 168 77 Example 19 142 3594 87 161 79 Example 20 135 342886 152 93 Comparative 136 3802 89 172 78 Example 12 Comparative 135 355887 166 81 Example 13 Comparative 120 3407 86 151 93 Example 14

The epoxy resin composition (i-1) in whichtris-(2,3-epoxypropyl)-isocyanurate having the mass ratio ofα-types:β-types=97:3 was modified and the epoxy resin composition (i-5)in which tris-(2,3-epoxypropyl)-isocyanurate having the mass ratio ofα-types:β-types=75:25 was modified showed almost comparable curingcharacteristics. The epoxy resin composition (i-2) in whichtris-(2,3-epoxypropyl)-isocyanurate having the mass ratio ofα-types:β-types=97:3 was modified and the epoxy resin composition (i-6)in which tris-(2,3-epoxypropyl)-isocyanurate having the mass ratio ofα-types:β-types=75:25 was modified showed almost comparable curingcharacteristics. The epoxy resin composition (i-3) in whichtris-(2,3-epoxypropyl)-isocyanurate having the mass ratio ofα-types:β-types=97:3 was modified and the epoxy resin composition (i-7)in which tris-(2,3-epoxypropyl)-isocyanurate having the mass ratio ofα-types:β-types=75:25 was modified showed almost comparable curingcharacteristics.

INDUSTRIAL APPLICABILITY

As described above, the present invention can provide a liquid or solidepoxy resin composition having excellent solubility and highpreservation stability, by modifying a crystalline epoxy resin.

The invention claimed is:
 1. A modified epoxy resin compositioncomprising: Compound A containing tris-(2,3-epoxypropyl)-isocyanuratehaving 1 to 3 glycidyl group(s) in a molecule substituted with afunctional group(s) of Formula (1):

wherein R¹ and R² are each independently an alkyl group, an alkenylgroup, an alkynyl group, an aryl group, an aralkyl group, a heterocyclicgroup; or a halogenated derivative, an aminated derivative, or anitrated derivative of these groups; and Compound B containingtris-(2,3-epoxypropyl)-isocyanurate, wherein: a molar ratio of CompoundA:Compound B is 90:10 to 30:70; tris-(2,3-epoxypropyl)-isocyanurate ofCompound A before the substitution andtris-(2,3-epoxypropyl)-isocyanurate of Compound B comprise 2% by mass to15% by mass of β-type tris-(2,3-epoxypropyl)-isocyanurate and aremaining percentage of α-type tris-(2,3-epoxypropyl)-isocyanurate basedon a total mass of tris-(2,3-epoxypropyl)-isocyanurate of Compound Abefore the substitution and tris-(2,3-epoxypropyl)-isocyanurate ofCompound B; and the composition is formed by: extracting β-typetris-(2,3-epoxypropyl)-isocyanurate from a crystalline body containingα-type tris-(2,3-epoxypropyl)-isocyanurate and β-typetris-(2,3-epoxypropyl)-isocyanurate using a solvent having about 20times increased solubility with α-typetris-(2,3-epoxypropyl)-isocyanurate versus β-typetris-(2,3-epoxypropyl)-isocyanurate, to obtain atris-(2,3-epoxypropyl)-isocyanurate crystalline body having an increasedcontent ratio of α-type tris-(2,3-epoxypropyl)-isocyanurate, andreacting the crystalline body with an acid anhydride of Formula (2):

wherein R¹ and R² have the same meaning as those in Formula (1).
 2. Themodified epoxy resin composition according to claim 1, whereintris-(2,3-epoxypropyl)-isocyanurate of Compound A before thesubstitution and tris-(2,3-epoxypropyl)-isocyanurate of Compound Bcomprise 2% by mass to 10% by mass of β-typetris-(2,3-epoxypropyl)-isocyanurate and a remaining percentage of α-typetris-(2,3-epoxypropyl)-isocyanurate based on a total mass oftris-(2,3-epoxypropyl)-isocyanurate of Compound A before thesubstitution and tris-(2,3-epoxypropyl)-isocyanurate of Compound B. 3.The modified epoxy resin composition according to claim 1, wherein thesolvent is methyl ethyl ketone, acetone, acetonitrile, ethyl acetate, orepichlorohydrin.
 4. The modified epoxy resin composition according toclaim 1, wherein the composition is soluble in a 83 wt % mixture of thecomposition in acid anhydride for at least 1 week at 25° C.
 5. Themodified epoxy resin composition according to claim 1, wherein thecomposition is soluble in a 83 wt % mixture of the composition in acidanhydride for at least 40 days at 25° C.
 6. The modified epoxy resincomposition according to claim 1, wherein the molar ratio of CompoundA:Compound B is 61.8:38.2 to 30:70.
 7. The modified epoxy resincomposition according to claim 1, wherein the molar ratio of CompoundA:Compound B is 48.2:51.8 to 30:70.
 8. A method for manufacturing amodified epoxy resin composition, the method comprising: Step (i):separating β-type tris-(2,3-epoxypropyl)-isocyanurate contained in atris-(2,3-epoxypropyl)-isocyanurate solution from the solution as asolid, and obtaining a crystalline body having an increased contentratio of α-type tris-(2,3-epoxypropyl)-isocyanurate from the solution;Step (ii): obtaining a tris-(2,3-epoxypropyl)-isocyanurate crystallinebody having a further increased content ratio of α-typetris-(2,3-epoxypropyl)-isocyanurate from the crystalline body obtainedin Step (i) by extracting β-type tris-(2,3-epoxypropyl)-isocyanuratewith a solvent having about 20 times increased solubility with α-typetris-(2,3-epoxypropyl)-isocyanurate versus β-typetris-(2,3-epoxypropyl)-isocyanurate; and Step (iii): reacting thetris-(2,3-epoxypropyl)-isocyanurate crystalline body obtained in Step(ii) with an acid anhydride, provided that a molar ratio of (glycidylgroups):(acid anhydrides) is 1:0.05 to 0.5, in order to obtain themodified epoxy resin composition, wherein the modified epoxy resincomposition comprises: Compound A containingtris-(2,3-epoxypropyl)-isocyanurate having 1 to 3 glycidyl group(s) in amolecule substituted with a functional group(s) of Formula (1):

wherein, R¹ and R² are each independently an alkyl group, an alkenylgroup, an alkynyl group, an aryl group, an aralkyl group, a heterocyclicgroup; or a halogenated derivative, an aminated derivative, or anitrated derivative of these groups; and Compound B containingtris-(2,3-epoxypropyl)-isocyanurate, whereintris-(2,3-epoxypropyl)-isocyanurate of Compound A before thesubstitution and tris-(2,3-epoxypropyl)-isocyanurate of Compound Bcomprise 2% by mass to 15% by mass of β-typetris-(2,3-epoxypropyl)-isocyanurate and a remaining percentage of α-typetris-(2,3-epoxypropyl)-isocyanurate based on a total mass oftris-(2,3-epoxypropyl)-isocyanurate of Compound A before thesubstitution and tris-(2,3-epoxypropyl)-isocyanurate of Compound B. 9.The method according to claim 8, wherein the solvent used for extractingβ-type tris-(2,3-epoxypropyl)-isocyanurate in Step (ii) is methyl ethylketone, acetone, methanol, ethanol, or isopropanol (2-propanol).